Respiratory mask



FIG. 1 is a perspective view of a respiratory mask showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a right side view, the left side view being a mirror image thereof.

The broken line showing is included for the purpose of illustrating environment and forms no part of the claimed design. 

CLAIM The ornamental design for a respiratory mask, as shown and described. 